ARS | Publication request: PUMPKIN (CUCURBITA MAXIMA AND C. PEPO), A NEW HOST OF BEET PSEUDO YELLOWS VIRUS IN CALIFORNIA.

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 3, 2003
Publication Date: January 20, 2004
Citation: Wintermantel, W.M. 2004. Pumpkin (Cucurbita maxima and C. pepo), a new host of beet pseudo yellows virus in California. Plant Disease. 88(1):82.

Interpretive Summary: Two species of pumpkin (Cucurbita pepo L. and C. maxima Duchesne) with extensive leaf chlorosis were identified in Monterey County, California during the summer of 2002. Symptoms resembled those caused by a group of whitefly transmitted viruses, known as criniviruses. Based on this information, standard laboratory tests were conducted to determine if the plants were infected by a Crinivirus, including northern blot hybridization and RT-PCR. These tests confirmed that the plants were infected with Beet pseudo yellows virus (BPYV). Additional fields with these symptoms were identified in 2003. In addition to confirmation using RT-PCR, a section of the virus was cloned and sequenced. Sequence information confirmed the virus was an isolate of BPYV. This is the first report of BPYV infecting pumpkin. BPYV is transmitted in a semi-persistent manner by the greenhouse whitefly, has an extensive host range, and is a widespread problem for greenhouse vegetable production. It is not clear what impact BPYV has on pumpkin production; however, the extensive chlorosis likely reduces photosynthetic activity and may influence plant growth and fruit size.

Technical Abstract: Pumpkin plants (Cucurbita pepo L. and C. maxima Duchesne) with extensive leaf chlorosis similar to those observed in Crinivirus infections were found in two locations in Monterey County, California during the summer of 2002. Leaves of diseased plants were observed to have large populations of greenhouse whitefly (Trialeurodes vaporariorum) present. Double-stranded RNA was Extracted from symptomatic leaves of these plants, and tested by northern hybridization for numerous criniviruses. A positive signal was identified exclusively with probes against the HSP70h gene of Beet pseudo yellows virus (BPYV), and confirmed by RT-PCR amplification of the BPYV minor coat protein (CPm) gene (2). Similar symptoms were observed in additional fields in 2003, and BPYV was again confirmed. In addition, the CPm RT-PCR product was cloned into a TOPO pCR2 vector using standard methods and sequenced. BLAST analysis of the cloned CPm RT-PCR product sequence corresponded to the published sequence of the CPm gene of BPYV (2) and Cucumber yellows virus (CuYV), a recently sequenced Crinivirus considered to be an isolate of BPYV (1). This is the first report of BPYV infecting pumpkin. BPYV is transmitted in a semi-persistent manner by the greenhouse whitefly, has an extensive host range, and is a widespread problem for greenhouse vegetable production. It is not clear what impact BPYV has on pumpkin production; however, the extensive chlorosis likely reduces photosynthetic activity and may influence plant growth and fruit size.